6 Replies Latest reply: Dec 27, 2010 5:37 PM by WZZZ
jayarr7 Level 1 Level 1 (10 points)
I think my iMac is running too hot and I suspect a defective fan. Downloaded Temperature Monitor and getting the following readings in Celcius. But I don't know what is normal. Are these normal temps?

Ambient Air 26C
CPU A Heatsink 48C
CPU A Proximity 52C
CPU Core 1 and 2 are both 51C
Graphics Processor Chip 1 57C
Main Logic Board 53C
Power Supply Position 1 79C

Thank you for any insight.

MBP 2.4 iPhone iMac 3.06 Dell Dim9200c Win7, Mac OS X (10.6.3), Lovely Machines
  • WZZZ Level 6 Level 6 (12,625 points)
    What's the drive doing? Everything looks OK except for the Power Supply at 79C. That is running way too hot.

    If you want to see the fan speeds to see if one is malfunctioning, get free iStat Pro

    http://www.islayer.com/apps/istatpro/
  • nachdenki Level 3 Level 3 (635 points)
    power supply can get pretty hot, but 79° seems a little too much. is it always this high? if that's the case, try an SMC reset
    http://support.apple.com/kb/HT3964?viewlocale=en_US
    if that doesn't help you might wanna phone apple about it and ask if this is a reason to get a repair
  • jayarr7 Level 1 Level 1 (10 points)
    Yes, I see the fan for the HD drive is at 0rpm. The others, cpu at 1299 and Optical at 911 are running.

    I should call Apple in the morning. Thanks for your help. Much appreciated.
  • WZZZ Level 6 Level 6 (12,625 points)
    Don't keep running it like that until it's fixed. Best of luck.
  • Saxman Level 2 Level 2 (175 points)
    My questions:

    1. How do you know what temps are "too high"? I can find no documentation anywhere giving me that information.
    2.. My Temp Monitor doesn't even show a Power Supply Position 1, only a PSP 2, is that odd?
    And while I guess my PSP2 at 69C is ok, my reading for "Secondary Heatsink" is showing 80C, is that high? Again, how are we supposed to know what is "too hot", only having the stats without anything to relate them to, is a bit wack.... Thanks..
  • WZZZ Level 6 Level 6 (12,625 points)
    1. How do you know what temps are "too high"? I can find no documentation anywhere giving me that information.


    Unfortunately, I don't think Apple publishes anything like this. You will have to fend for yourself. Ask around and get an impression of what others with the same or similar computer are experiencing. But don't settle for the answer that you have nothing to worry about since, if it gets too hot, it will shut down. This is true, but not very helpful if your Mac is operating too hot or near its shutdown threshold for long periods. And, I agree, without anything published based on actual research and evidence, just having someone tell you that a given temp is OK or not isn't necessarily very reliable. There is the widely held opinion that Apple in its desire to have quiet running computers, allows temps to climb unreasonably without ramping up the fans, thereby allowing damage to the hardware over the long haul. I would like this computer to last much longer than three or even five years. At five years, however, it will be classified by Apple as "vintage." And, perhaps, that is Apple's life expectancy, so it's possible thermal design for a longer period of time may not be foremost in the minds of Apple engineers. There is the counter argument that Apple has engineered the thermal design of the computer for optimal performance. From things I've heard here and there, I'm somewhat biased towards the first opinion. I use smcFan Control. Sorry, can't be more helpful.

    2.. My Temp Monitor doesn't even show a Power Supply Position 1, only a PSP 2, is that odd?

    And while I guess my PSP2 at 69C is ok, my reading for "Secondary Heatsink" is showing 80C, is that high?

    I can't help with the Secondary Heatsink question, but I have two programs that read temperature, Hardware Monitor and iStat Menus. Hardware Monitor shows a readout for Power Supply Position 2, while iStat Menus has recently renamed that readout "Board Proximity." My guess would be that the PSP2 sensor isn't mounted directly on the Power Supply, but somewhere adjacent or in the vicinity and that's why it's been renamed. Perhaps PSP1 is a sensor mounted directly.

    Any given machine will have only a certain set of sensors. Not all current Macs have sensors at the same places or senors which are necessarily supported by the system. For example, for some reason I don't have a readout for the Nvidea GPU on mine -- even though Nvidea has told me it includes a sensor -- where ATI Radeon GPUs are supported in other models.

    Here's something you might want to read on Hard Drive life and temperature. It's a few years old.

    http://www.codinghorror.com/blog/2006/12/hard-drive-temperatures-be-afraid.html

    FWIW here are my current operating temperatures. I'm in a cold room -- we have a heat problem right now -- and not doing anything intensive with the computer. Disregard the Ambient Air reading, which is inaccurate; the room is really around 64F. In summer these numbers will be higher. Even now, if the room were warmer, you could add a few degrees Celsius to these.

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